How to replace a dull sky in Paint by Zaweba

A flat white sky can ruin an otherwise good landscape, property photo or holiday picture. Replacing it used to mean a careful selection round every roof and tree, a new sky layer, and then a lot of work to make the foreground look as if it had been lit by the new sky. Sky Replacement in Paint by Zaweba handles most of that in one dialog.

You'll find it under Edit > Sky Replacement. It works on your own computer with no online service, and it finds the sky with a classic matte rather than an AI model.

How it finds the sky

The tool looks for areas that are bright, smooth and connected to the top of the frame, which describes most skies. It then refines the edge with a guided filter, which follows fine detail such as branches and the edges of buildings far better than a simple selection. Everything that isn't sky becomes the foreground.

Because it looks for bright, smooth areas connected to the top, it works best on clear, ordinary scenes: a building against a grey sky, a field and a horizon, a beach. Very busy skylines or skies broken up by lots of foliage may need some help with the mask afterwards.

The settings

Shift edge moves the boundary between sky and foreground inward or outward, useful when a thin halo of the old sky shows along a roofline. Fade edge softens the boundary so the join is less abrupt.

Scale, move and flip position the new sky. Make sure the sun or the brightest part of the new sky is on the same side as the light in the foreground, or the picture will look wrong even if the edges are perfect. Flip is the quick fix when they don't match.

Brightness adjusts the new sky to sit with the rest of the picture.

Foreground lighting is the setting that makes the result convincing. It tints the foreground towards the colour of the new sky, so a warm sunset sky brings warmth to the buildings and people below.

All of this is shown with a live preview, so you can see each change on the photo straight away.

What you get

The result is a group of layers rather than flattened pixels: a masked White Balance layer that provides the foreground lighting, and the masked sky. Because they are separate and masked, you can fix things after the event. Paint on the masks to tidy an edge, lower the White Balance layer's opacity if the tint is too strong, or move the sky layer to reframe it.

Getting a natural result

Choose a sky that fits. Match the time of day, the direction of the light and the height you are looking from. A dramatic sunset over a scene lit by harsh midday sun never looks right.

Watch the reflections. Water, windows and shiny cars reflect the sky, and they will still show the old one. A quick touch-up on those areas with the new sky colours makes a big difference.

Check the edges at full size. Fine branches and hair are the hardest. A little fade edge often hides any remaining halo, and a brush on the mask cleans the rest.

Keep it honest when it matters. Property listings and news photos have their own rules about editing skies, so make sure a replacement is acceptable where the picture will be used.

Where it fits

Sky Replacement pairs well with the other photo tools in Paint by Zaweba. Haze Removal can bring back distant detail in the foreground, and Clarity adds depth to the new clouds. If the photo is a RAW file, develop it first in the RAW Developer, then replace the sky on the finished image.

Done with care, a new sky can turn a dull record shot into a picture people want to look at.